Wrong calculation of rolling resistance

[LBodnar]

For Mz I suggest using this:

Code:

btScalar CARTIRE::PacejkaMz(btScalar sigma, btScalar alpha, btScalar Fz, btScalar gamma, btScalar friction_coeff, btScalar & max_Mz) const
{
    btScalar Input_alpha = alpha;                // save slip angle on entry
    if (alpha > 90.0) alpha = 180.0 - alpha;    // symmetry around +90 degrees if caller missed it
    if (alpha < -90.0) alpha = -180.0 - alpha;    // symmetry around -90 degrees if caller missed it

... calculations

    // anti-symmetry around +-90 degrees
    Mz *= cos(Input_alpha * M_PI / 180.0);
    return Mz;
}

Here is what we get as a result compared to existing formula. Of course anything beyond 10-20 degrees slip angle is already a heavy slide but at least we get common sense outputs in this calculations.

Caller still has to limit the input slip angle to +-180 degrees!




Update: Haha! I have just had a look in Pacejka's 2006 book and he includes cos(alpha) factor in Mz stating

factor cos(a) appearing in the equations for the aligning torque to properly handle the case of large slip angles and possibly backwards running...

:lol: